Yes Ian and Dave that is the one. Interesting it is for a 1953 onwards though. My car is a late 1952 it seems so this must have been fitted as a replacement at some time. Mick I am in the Old Kent Road area tomorrow working so I may well pay John a visit. I have looked at replacing the brass fitting coming out of the motor with a post and use a external solenoid with a push to start button.
Just re read Micks post and Monday is a no no. Oh well have to see if I can get a job there later in the week.